Reciprocating screen



NOYj. 19A, I l w 1 PARKS 2,222,299

RECIPROCATING SCREEN Filed July 27, 1957 5 Sheets-Sheet l ATTORNEYS.

Nov. 19, .1940. w. J. PARKS RECIPROCATINGv SCREEN Filed July 27, 1937 INVENTOR CJaZeff J'. Par/6 ATTORN 3 Sheets-Sheet 2 Nov, 19, 1940. w. J. PARKS 2,222,299

' v v RECIPRQGATING SGREENy l Filed July 27, v193'? sheets-sheet 5 INVENTOR,

BY. gai??? ffpa/s 62% MATORS.

Patented Nov. 19, 1940 UNITED STATES 2,222,299 nEolrnooA'rlNG SCREEN WalterJ. Parks, Shaker Heights, Ohio Application July 27,

7 Claims.

The present invention relates to reciprocating mechanism whereina body, such as a screen frame, is caused to have reciprocating motion by means of an actuating mechanism such as a drive shaft and an eccentric.

It is the general object and nature of my invention to eliminate vibrations and vibrating forces set up in such a mechanism by means of compensating for and counter-balancing the lo mass inertia of the reciprocating body with an opposing mass inertia, and the forces generated in the resilient supports of the reciprocating body with opposing and reacting resilient forces.

My invention is particularly adapted for ap- .15 plication to screening apparatus wherein the reciprocating body of the mechanism constitutes the screen frame or screen b dy, and wherein such reciprocating body is disposed in a horizontal plane and intended for so-called ilat 2@ angle operation.

Briefly outlined, the invention consists of a reciprocating body or screen frame resiliently mounted upon a supporting member or base frame, together with an actuating mechanism 5 comprising a drive shaft and an eccentric, and a counter-balancing mass rotatably mounted upon the supporting member at a point removed from the center of gravity of the mass, and means for connecting the drive shaft and eccentric between 35i the reciprocating body and the rotatable mass,

so that the reciprocating or translational movement of the reciprocating body is balanced by the rotational movement of the mass. The invention also includes resilient means connected to the rotatably mounted mass so that the forces generated 'therein will counteract and counter-balance the forces generated in the resilient mounting of the reciprocating body.

It is an established physical law that a body 1@ suspended for rotation about an axis, not at the center of gravity, may be struck at a certain point, termed the center of percussion, without causing any pressure on the axis passing through the point of suspension. The center of percusib sion may be defined as the point of application of all forces 'tending to cause a body to rotate aboutJ a given axis.

As there is no force, other than the Weight of the body, acting through the axis of suspension,

@9 when the body is acted on by a force at, right angles to the centerline through the axis of suspension and the center of percussion and at the center of percussion, the body may be resiliently supported at this point and no movement of the axis will take place.

1937, Serial No. 155,878

For each axis of suspension and a given set of operating conditions the center vof percussion will vary but for a given set lof conditions and a given axis of suspension the center lof percussion will remain in a given location. It is also important to note that if the body is suspended from the center of percussion the original axis of suspension will then become the center of percussion.

The fundamental object and principle of operation accomplished by a reciprocating mechanism embodying my invention is therefore to balance the actuating force applied to and acting through the center of gravity of the reciprocating body having a translational motion by opposing force generated and acting through the center of percussion of the body having rotational motion. Additional objects and advantages shall become apparent as the following description proceeds.

To the accomplishment of the foregoing and related ends, said invention, then, consists of the means hereinafter fully described and particularly pointed out in the claims.

The annexed drawings and the following description set forth in detail certain mechanism embodying the invention, such disclosed means constituting, however, but several of various mechanical forms in which the principle of the invention may. be used.

In said annexed drawings- Fig. l is a side elevational View of one form of apparatus embodying the principle of my invention; Fig. 2 is an end elevational view of the apparatus shown in Fig. l; Fig. 3 is an enlarged, detail sectional view of a portion of the drive shaft and taken substantially along line 3 3 of Fig. 2; Fig. 'i is an enlarged, detail sectional View of the counter-weight mounting and taken substantially alongline di-d Fig. 1; Fig. 5 is an enlarged, detail sectional view of the connecting rod connection to the counter-weight and taken substantially along line 5-5 of Fig. l; Fig. 6 is a view similar to Fig. 5, but illustrating an alternative forni of construction; Fig. 7 is a side elevational view showing a modified form of construction for apparatus also embodying the princple of my invention; Fig. 8 is an end elevational view of the apparatus shown in Fig. 7; Fig. 9 is a detail view illustrating an alternative form of mounting of the counter-weight shown in Fig. 7, to the base frame; Fig. l0 is a fragmentary, end elevational view of the apparatus shown in Fig. 7, but of the end opposite to that shown in Fig. 8; Fig. l1 is an enlarged, detail sectional view of the mounting of the counter-weight of the apparatus shown in Fig. '1 and taken substantially along line II-II thereof; Fig. 12 is a fragmentary side elevational view showing a modified form of construction for the form of apparatus shown in Fig.

` 7; Fig. 13 is a side elevational view of a third alshown in Fig. 13.

Now referring more particularly to Figs. 1 to 6 of the drawings, there is shown therein a supporting member or base frame consisting of the longitudinal channels I mounted upon the transverse I-beams 2.

A screen frame 3 carrying one or more screen decks such as the decks 4 and 5 is resiliently mounted upon the base frame by means of the rubber blocks 6 secured or otherwise suitably attached to the metal brackets 1`and 3 1;

` This rubber bushing is cured to inner and outer carried by the frame 3 and the channels I respectively.

i drive motor (not shown) is mounted on one end of the vldrive shaft 9. 'Ihe drive shaft 9 has an eccentric portion I3 upon which the connecting rod I4 is journalled at one end by means of the bearing I5. An eccentric counter-weight I6 is mounted upon the main portion of the drive shaft 9. ,to counterbalance the eccentricity of the shaft portion I3 and the parts which are eccentrically mounted thereon.

The connecting rod I4 is connected at its other l end to the wrist pin I6 through the bearing I1.

The wrist pin I6 is mounted in the arms I8 exltending from the reaction member or counter- `Weight `I9 which in turn is rotatably supported upon the members I of the base frame by means of the shaft 20 journalled in the bearings 2|. The drive shaft 9 is located substantially at the center of gravity of the screen frame 3. g 'I'he connecting rod I4 is connected substantially to the center of percussion of the counterweight I9 which has its axis of rotation or center of suspension on the shaft 20. Thus the line of action of the connecting rod I4 passes through 1 the center of percussion of the reaction member lor counter-weight I9 and also substantially `through the center of gravity of the screen frame 3.

y Resilient means consisting of the rubber blocks 22 are connected between the counter-weight I9 and the housing 23r which in turn is secured to the base frame members I. Thus the resilient means consisting of the rubber blocks 22 is located substantially in line with the center of percussion of the counter-weight I9 and the line of action of the connecting rod I4.

The lines a, a, in Fig. 1 represent the line of action of the resilient forces generated in the rubber mounting 6 on the screen frame 3. The lline c represents the line of action of the connecting rod I4 and of the resilient forces generated in the rubber mountings 22. By reference to the distances denoted X and Y respectively, it will be seen that the line of action of Ithe resilient forces generated in the resilient `connections or rubber mountings 22 of the `counter-weight I9 on the screen body is substantially midway between the lines of action a `of the forces generated in the resilient supports `Ii of the screen frame 3. In this manner, not only are the resilient forces of both the reciprocating bodies or screen i'rame 3 counterbalanced and opposed by the resilient forces generated in the resilient supports of the rotatably mounted reaction member or counterweight I9, but any lturning moment or rocking couple tending to have an effect upon the reciprocal movement of the screen frame 3 is eliminated.

The resultant line of motion of the screen frame 3 will be along the line c or 4the line of action of the connecting rod I4. Thus, in order to compensate for the reciprocal movement of the drive pulley I2, the axis of the drive motor should be located at a point along the line D, D which is normal to the line of reciprocal motion c.

In the alternative form of construction shown in Fig. 6 for the connection of the connecting rod I4 to the counter-weight I9, a rubber bushing 23 is substituted for the anti-friction bearings I1.

metal tubes 24 and 25 which inturn arekeyed to the shaft I6 and connecting rodl I4, respectively. The rubber bushing 23 will permit the connecting rod I4.t`o tilt or pivot through the necessary angle of operation.

In the form of construction just described, and shown in Figs. 1 to 6 inclusive, the drive `shaft, it will be noted, is mounted upon and carried by the reciprocating body or screen frame 3, and thereby increases the total weight of such body, requiring a coincident relative increase in the Weight of the reaction member or counter-weight I9. In the form of construction shown in Figs. '1 to ll inclusive, the drive shaft or actuating mechanism is supported by the reaction member or counter-Weight, thus.

decreasing the total mass of the reciprocating screen body and increasing the Weight of the reaction member. v

vReferring more particularly to Figs. 7 to 11, the screen frame 30 is supported by means of the rubber mounting blocks 3l on the stationary base frame 32. The reaction member or counterweight 33 is rotatably mounted upon the shaft 34 carried by the frame 32 by means of the rubber bushing 35. 'I'he drive shaft 36 is journalled in the lower end of the counter-weight 33 and eccentrically connected by means of the connecting rods 31 to the screen frame 30. The connecting rods 31 in this particular instance are in the form of laminated or leaf springs. thus accommodating the lateral movement of the eccentric drive between the points of connection. A 'resilient mounting 38 consisting of a rubber block connects the lower end of the l counter-weight 33 to the housing 39 extending downwardly from the base frame 32.

Fig. 9 illustrates an alternative form of mounting for the axis of rotation of the counterweight 33, and wherein flanges 40 and 4I, spaced apart by the rubber mounting 42, are carried by the counter-Weight 33 and the base frame 32 respectively. The center of suspension is located between the flanges 4l) and 4I and substantially in the center of the rubber mounting 42, as indicated at 43. Compression of4 the rubber mounting 42 between the flanges 40 and 4I permits the counter-weight 33 to oscillate or rotate about such center of suspension.

Again, in connection with the form of apparatus just described and shown in Figs. 7 to 11 inclusive, it will be seen that the line of action c of the connecting rod 31 passes substantially through the center of gravity of the reciprocating body or screen frame 30 and through the center of percussion of the reaction member or counterweight 33; and that the resilient means connecting the end of the counter-weight 33, viz., at a. point removed from its axis of rotation, is substantially in alignment with the center of percussion and the line of action c. Since the drive shaft 36 and the drive pulley M move with the counter-weight 33, the axis of the driving motor should be preferably in alignment with the axis of rotation of the counter-weight 33.

In the modified form of construction shown in Fig. 12, the drive shaft 50 is mounted midway between the screen frame 5| and the counterweight 52 by means of the leaf spring connecting rods 53 and 54, so that the weight of the drive shaft 50 is equally distributedbetween the two relatively moving bodies. In this latter form of construction, two eccentrics are provided upon the drive shaft 50, and these eccentrics are lo cated 180 apart and each respectively connected to the connecting rods 53 and 54. In this manner, the drive pulley for the drive shaft 50 would not have to be eccentrically mounted on the shaft and therefore would not be subjected to any axial shifting of position, so that the drive motor can be located in practically any desired position.

In the third alternative form of construction, as shown in Figs. 13 and 14, both the reciprocating body and the reaction member are pendantly supported and resilient mountings and connections are eliminated. In this latter form of construction, the screen frame 60 is pendantly supported from the base frame 6I by means of the hangar bars 62 and 63 which are pivoted at their upper ends 64 and 65 respectively to the frame 6I and pivotally connected at their centers of percussion 66 and 61 to the screen frame 60. The reaction member or counter-weight 68 is pivotally connected at 69 to the supporting frame 6i and carries the drive shaft 10 located substantially at its center of percussion. A connecting rod 1| is eccentrically connected to the drive shaft 10 at one end and pivotally connected at the other end as at 12 to the screen frame 60. Here again the line of action c" of the connecting rod 1I passes through the center of gravity of the screen frame 60 and through the center of percussion of the counter-weight 68. The drive pulley 13 mounted on the drive shaft 10 will of course be subjected to axial reciprocation, so that the drive motor should be mounted in alignment with the axis of rotation 69 or center of suspension of the counter-Weight 68.

From the foregoing description of the apparatus embodying the principle of my invention, and the explanation of the mode of operation thereof, it will be seen that I have provided means for eliminating vibration in reciprocating mechanisms wherein a reciprocating body having a motion of translation and a second body having a motion of rotation are counter-balanced by means of actuating forces, acting through the center of gravity of the former body and through the center of percussion of the latter body, such actuating forces offsetting and opposing each other so that there are no residual forces or vibrations transmitted to the base structure or supporting member.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the mechanism herein disclosed, provided the means stated by any of the following claims or the equivalent of such stated means be employed.

I therefore particularly point out and distinctly claim as my invention:

l. In a reciprocating mechanism, the combination with a frame, a body resiliently supported on said-frame, a mass oscillatably mounted on said frame at a point removed from the center ofgravity, said point being so positioned that the center of percussion of said mass is located at one end thereof, actuating means adapted to impart reciprocating movement to said body connected between said body and mass at substantially the center of ,percussion of the latter with respect toits axis of oscillation, and resilient means connecting said mass to said frame in substantial alignment with the line of connection of said actuating mechanism with the body and mass.

2. In a reciprocating mechanism, the combination with a frame, a body resiliently supported on said frame, a mass oscillatably mounted on said frame at a point removed from its center of gravity, said point being so positioned that the center of percussion of said mass is located at one end thereof, actuating means adapted to impart reciprocating movement to said body connected between said body and said mass at substantially the center of percussion of the latter with respect to its `axis of oscillation, a. bracket carried by said frame and resilient means interposed between said bracket and mass in substantial alignment with the line of connection of said actuating means with the body and mass, and so positioned as to be in shear.

3. In a reciprocating mechanism, the combination with a frame, a body resiliently supported on said frame, a mass oscillatably mounted on said frame at a point removed from the center of gravity, said point being so positioned that the center of percussion of said mass is located at one end thereof, actuating means carried by said body adapted to impart reciprocating movement to said body connected between said body and mass at substantially the center of percussion of the latter with respect to its axis of oscillation, and resilient means connecting said mass to said frame in substantial alignment with the line of connection of said actuating mechanism with the body and mass.

4. In a reciprocating mechanism, the combination with a frame, a body resiliently supported on said frame, a mass oscillatably mounted on said frame at a point removed from its center of gravity, said point being so positioned that the center of percussion of said mass is located at one end thereof, actuating means carried by said body and located substantially at the center of gravity thereof adapted to impart reciprocating movement to said body connected between said body and mass at substantially the center of percussion of the latter with respect to its axis of oscillation, and resilient means connecting said mass to said frame in substantial alignment with the line of connection of said actuating mechanism with the body and mass.

5. In a reciprocating mechanism,l the combination with a frame, a body resiliently supported on said frame, a mass oscillatably mounted on said frame at a point removed from its center of gravity, said point being so positioned that the center of percussion of said mass is located at one end thereof, a drive shaft journaled in said frame, and a longitudinally rigid connecting arm eccentrically connected at one end to the drive shaft and at its other end to substanr stantiai alignment with the line of connection of the connecting arm with thel shaft and mass, and so positioned as to be in shear.

6.In a. reciprocating mechanism, the combination with a frame, a body resiliently supported on said frame, a mass oscillatably mounted on said frame at a point removed from its center ofv gravity, said point being so positioned that the center of percussion of said mass is 1ocated at oneend thereof, longitudinally rigid connecting arms. extending toward each other from substantially the center of percussion of said mass with respect to its axis of oscillation and from substantially the center of gravity of said body, respectively, a drive shaft eccentrically carried by adjacent ends of said arms, and resilient means connecting said mass to said frame in substantial alignment with the line of connection of said connecting arms with the body and mass.

7. Ina reciprocating mechanism, the. combination with a frame. a body reslliently supported on said frame, a mass oscillatably mounted on said frame at a point; removed from vits center of gravity, said point being s o positioned that the center of percussion of said mass is located atone end thereof, a drive shaft carried .by said mass and located substantially at the center of percussion oi' the latter with respect to its axis oi oscillation, a longitudinally rigid connecting arm eccentrically connected at one end to the drive shaft and at its other end to said body at a point substantially in alignment with the center of gravity thereof and said center of percussion and resilient means interposed between the frame and mass in substantial alignment with the line oi' connection of the connecting arm with :the shaft and mass, and so positioned as to be in shear. 

